The Thai people, or formerly Siamese, are the main ethnic group of Thailand and are part of the larger Tai ethnolinguistic peoples found in Thailand and adjacent countries in Southeast Asia as well as southern China. Their language is the Thai language, which is classified as part of the Tai–Kadai family of languages, and the majority of Thai are followers of Theravada Buddhism. “Thai people” usually includes Central and Southern Thai (Siamese proper), Northern Thai (Lanna) and Isan people.